With the progress of the digital technology of electronic devices in recent years, nonvolatile semiconductor memory devices with a large capacity have been actively developed for storing data, such as music, images, and information. For example, nonvolatile semiconductor memory devices which use ferroelectrics as capacity elements have already been used in many fields. Furthermore, other than the nonvolatile semiconductor memory device which uses such a ferroelectric capacitor, a variable resistance nonvolatile semiconductor memory device (hereinafter referred to as a ReRAM) including a variable resistance element whose resistance value changes in response to an electric pulse application and which holds the state has been attracting attention in that it is easy to ensure consistency with a general semiconductor manufacturing process.
A cross point ReRAM has been proposed as a variable resistance nonvolatile semiconductor memory device in order to reduce size and increase capacity (e.g., see patent literature (PTL) 1). Patent literature 1 discloses a nonvolatile semiconductor memory device having a configuration in which a diode is placed in series with respect to a variable resistance layer. This is for avoiding effects from variable resistance layers in other rows or columns, when the resistance values of the variable resistance layers formed at cross-points where lines for rows and columns cross are read. According to PTL 1, at least one layer among an electrode layer and an insulating layer (or a semiconductor layer) included in a diode that is a non-ohmic element is embedded in a contact hole formed in an interlayer insulating film. With this, a surface which is in the same plane as the interlayer insulating film and is significantly smooth can be formed, which makes it possible for the non-ohmic element to have a good interface state. As a result, according to PTL 1, it is possible to reduce decrease or variation in a breakdown voltage due to an electric field concentration or the like, and increase a current capacity.